Manufacture of cement



W. M. KEENAN MANUFACTURE OF CEMENT Filed July 17 1928 4 Sheets-Sheet lINVENTOR WgterM. Keenan v I Oct. 31, 1933. w M KEENAN 1,932,467

MANUFACTURE OF CEMENT Filed July 17, 1928 4 heets-Sheet 2 INVENTORyd/[Pr Al. Keenan ATTORNEY Oct. 31, 1.933. w. M. KEENAN MANUFACTURE OFCEMENT Filed July 17, 1928 4 e shee 3 v INVENTOR v iarfifl KR??? f r ch31, 933. w. M. KEENAN 1,932,457

MANUFACTURE OF CEMENT Filed July 17, 1928 4 Sheets-Sheet 4 INVENTOR ferM0 Kmwa'm I 1 :{w .w" (4, TTORNEY Patented Oct. 31', 1933 UNITED, STATESPATENT OFFICE 1,932,467 I Q i MANUFACTURE OF CEMENT Walter M. Keenan,New York, N. Y., assig'nor, by

mesne assignments, to Metropolitan Engineering Company, a corporation ofNew York Application July 17, 1928. Serial No. 293,434

2 Claims. (craze-7) The object of the invention is to effect economy offuel in the production of cement. The usual method of producinghydraulic cement is to -pass the ground material through a long inplinedrotary kiln and to pass combustion'gases through the kiln in theopposite direction.

My invention such a method with considerable economy of I fuel. f

The accompanying drawings illustrate 'embodiments of the inventiondiagrammatically. The details of such apparatus are well known and maybeof any usual or suitable design.

. 1' is a longitudinal section of the. exit end of the kiln andapparatus connected therewith;v V

is evaporated from the slurry. ;W0rking in .this

'- Fig. 2 is'ja similar view of a modification;

Fig. 3 is a similar view'of another modification; Fig. 4 is a similarview of an alternative to i' Fig. '5 is Fi .'-.4.' I

'Befer-ring'firstto Fig. 1, the rotary kiln is indicated at 1. The gastherefromisdischarged into. aheader 2. In charge, is a damper '-3 forregulating the outflow of gas. At the lower endof the header is a:dust,

' pocket'3 The gas passes by a conduit 4 into a boiler comprisinginclined tubes.5, betweenheadersfi'and '7, and a steam drum 8. B'aflles9 and 10 direct the gasesover the tubes," and dust pockets l1 and 12catch additional quantities .of

dust. I The. gas-tram the boiler may pass by w'ayof 'a fine 13 tofaneconamizer and thence to'a-drynr 3 for the material entering the kiln.It is preI- arable, however, to lead-the gas fromthe waste heat boilerthrough aflu 14'direct to the dryer,

usingother means for heating the boiler feed- ,water.

: The dryer illustrated is otthecontact type comprising a cylindricaltower through which the bottom to top. At intervals ingas passes fromthe height there are annular trays 16 and central tray 16?. A=centrallyarranged shaft 1'7 is 4 rotated by an overhead motor '18. and carriestwo -'sets of rotary plows arranged alternately. The

plows 19 engage the materialon thetrays and gradually force it inward tothe center where it drops onthe plows '20. which gradually force it 50outward to'drop on the next lower tray. The hot with the materialgaspasses upward in contact and out through the flue 21'and exhaust 1an'22to the stack;2'3-. The; wet ground material the form ot .a,slurry is fedin' 'atthe top through a pipe 24; It isheated and dried, completely orprovides for the operating of :the use of such a cross-section onthe"line' ot the header, below' the dis- ;cost of the slurry dryer,,efliciently dried. by passing itf through passages separated fromvthegas by. metal walls whichto that of Fig. 1

'end of the. kiln.

It is common to use waste heat boilers,' The i present process, however,isope'rated to effect a considerable saving beyond that resulting fromboilers. The installation isdesigned to maintain a'high temperature ofthe gas. at the exitfrom the boiler, say 500 to 600 "degrees F. (or 300to 400 degrees Fpaiter pass- 2 ing" through an conomizerl. With a texiiperature of 550 degreesfor the flue gas' fromthe boiler and about-100degrees for the gas-leaving the slurry dryer, about' 89 per cent of thewater way, there is a very substantial .saving'of coal or other fuelover the'old method in which the dryers are-fired separately and in amanner sim-v ilar to that of firing the kilns.

For example, with the temperatures above stated; the" calculated economyfor an ordinary modem plant amounts to 10 or 12 per cent of the fuelburned. .Stated in another way, the figures indicate a saving of morethan a short ton of coalperhour in operating a 4000 barrelplant.

Various other metho'dsmay be used for applying the heatof the exhaustgas from the kiln, the waste heat boiler 01'', the economizer to thematerial'before it enters-the kiln. Direct contact methods-such as thatoffFig. l have the advanta'ge of washing the gas =and"so far eliminatingthe dust remaining therein as to avoid the necessity of'a. dustcollectofl-smthat' th'e cost of such a, cdllector may ,be'" crediteda'gainstthe' But the slurry maybe may take any desired form, such','forexample,

'as' tubes or fiat plates; Or indirect methods may be used whereinj air,hot water-or steam heated -.by'the exhaust gas may beapplied invariousways to the dryingof the slurry-1 Fig. 2 i-llu strates a second contactmethod. The exhaust flue 14 directs the hot gas over the 'slurry at thelatter is'lead through branch pipes 28- to revolving platesorcentrifugal mixers 29 actuated by motors30.- The gas passes out near thebottom of the I mixer chamber 31 to the exhaust flue '21. The dried orheated slurry drops to a hopper 25 whence it is fed to agkiln; theremaininglpart of the installation being similar The exhaust gas' may beused by bubbling it through the slurry or passing it'qver'th surface ofthe latter, or by other direct contact methods. The invention isapplicable also with considerable economy to dry processes ,of makingce- Fig. 3 shows the kiln 1 lined for the majorpart of its length with arefractory lining 32 and at its lower end a housing 33 which is onrollers and which houses a coal dust nozzle or burner 34 projecting aflame into the kiln. Within the shell of the kiln the lower portion hasa lining of water tubes 35 instead of the refractory material 32. Thetubes may be spaced apart as in Fig. 5 and have longitudinal fins 36welded to them and overlapping 'or substantially closing theintermediate spaces, though free to expand and contract independently,and may be backed by refractory material 1.

Other styles of lateral extensions or fillers may be used. Or suchextensions may be omitted, the tubes being arranged close together orbeing spaced apart from one another according to the conditions withinthe kiln. The jet of flame can be regulated to give a very hightemperature and a surplus of heat compared with that which is ordinarilyused.

In the usual refractory lined kiln, it is necessary to avoid the highesttemperature attainable with nozzle burners in order to safeguard therefractory lining. The temperature is maintained below the danger .pointby the use of excess air. The highertemperature could be used as far asthe burning of the cement is concerned, but a compromise is made inorder to decrease the maintenance charges for refractory linings. The

water wall of tubes, however, permits the opercommunicate at their endswith annular'headers 36 and 37 surrounded by perforated rings 38 and 39on the outside whichform the inner faces of annular channels 40 and 41within which the kiln rotates. Connected to the upper channel41 is asteam pipe 42 with a flexible connection 43 to allow for irregularmovement of the kiln.

The steam pipe leads into a drum 44 from which the steam is taken ofithrough a pipe 45. Feed' water from a pipe 46 enters the drum, and thewater from the drum passes by a pipe 47 with a flexible joint 48 to thechannel 40 and thence to the lower header 36. t

The gas discharged-from the upper end of the kiln is still hot enough tobe used for drying the material and is passed by a flue 49 to a slurrydryer 15 similanto that of Fig. 1, or any other drying apparatus aspreviously explained.

Where the material is dry enough it may feed into the kiln through apipe 50 by gravity. Of if necessary a screw feed may be used as in Fig.1.

A similar water tube lining may be added farther along the kiln, toserve the purpose of an economizer in heating water to be supplied tothe steam generator. Or a water heater may be substituted for the steamgenerator of Fig. 3.

Fig. 4 shows a hot water system operated through the water tube lining,the rest of the structure being like that of Fig.3. A feed pump 51forces water through a pipe. 52 with a flexible connection 53 to the lowerchannel 40, whence it passes up through the header 36 and tubes 35and upper header 37 to the channel 41 and thence through a pipe 54 witha flexible joint 55 to the point of utilization.'

- Whatever design of apparatus is used, it is so proportioned andoperated as to leave a surplus after 'generatingsteam or heating feedwater or both, which can be efficiently applied to the preliminarydrying of the material.

Various other modifications may be made by the invention as defined inthe following claims.

I claim:

1. An apparatus for the production of cement comprising a rotary kiln, anozzle burner projecting a flame therein and a water wall within thelower end of the kiln, said. water wall comprising longitudinal tubeslining the shell, headers at opposite ends of said tubes and means forcirculating. water through said tubes from the lower to the upper endsand taking off hot water or steam from the upper header.

2. Apparatus for the production of cement comprising a rotary kiln, anozzle burner projecting a flame therein and a water wall within thelower end of the kiln, said water wall comprisinglongitudinal tubeslining the shell and having flanges extending from' said tubes to closethe lating water through said tubes.

WALTER M. IKEENAN.

those skilled in the art without departing from I

